Image:Paranthropus walkeri skull front view

Cast of the ‘Black Skull’ KNM-WT 17000 discovered in 1985 by Alan Walker in West Turkana, Kenya. The skull dates to 2.5 million years old and gets its name from the fossil's colour (caused by a high manganese content). There were problems with classifying this skull when it was first found as it has a mixture of primitive and derived traits. It was originally assigned to the species Australopithecus boisei but was later reclassified. It is sometimes called P. aethiopicus.

Notes

The skull has small brain vault size of 410 cc, one of the the smallest for any fossil hominin. Key features are the flaring zygomatic arches (the bones around the side of the skull that form the cheeks), large cheek teeth and a prominent sagittal crest that is more to the rear of the skull than in other Paranthropus species. These features were adaptations for heavy chewing. It also has a very projecting face compared with other Paranthropus species.